Proposal 1: Protection against radiation damage of the host immune response by immune adjuvants. The effect of x-radiation and immune adjuvant, alone and in combination on a mouse and rat tumor will be investigated. Proposal 2: Release of tumor specific antigen following local irradiation and its effect on the nature of the hose immune response to the tumor. Tumor associated transplantation antigens (TATA) separate from tissue antigens have been shown by others to be present in tumors. The techniques for studying tumor-associated antigens in rat and mouse serum before and after radiotherapy we have utilized primarily are macrophage migration inhibition, and cellular cytotoxicity to tumor cells. We have also initiated immuno diffusion, immuno-electrophoresis, and membrane immunofluorescence techniques. Proposal 3: Examination of a new class of immune adjuvants - polycations. The activation of macrophages in immunologically specific ways by hyperimmunized spleen cells and by supernatant factor from immunized spleen cells, and in immunologically non-specific ways by endotoxin or double stranded RNA, was reported by Alexander and Evans. It is postulated that polycations likewise activate macrophages in non- specific fashion. This will be investigated by cell cytotoxicity.